For a long time thermostats for central heating systems were relatively simple devices, providing basic functionality for controlling the temperature in an environment and connected to a central heating boiler via a wired connection.
Recently, more advanced devices have been developed, which provide more flexible control over central heating systems and can, in some cases, be remotely controlled, for example using an application on a tablet computer or smartphone. Furthermore, some wireless designs no longer require a wired connection to the boiler, instead communicating wirelessly with a receiver device connected to the boiler, which affords much greater flexibility in where the thermostat can be installed. For convenience, such devices may be battery-powered, but the power needs are typically much greater than for other types of domestic environmental sensors, such as smoke alarms, which typically only require batteries to be changed very infrequently. In such cases, it does not matter greatly if the device is constructed in such a way that access to the battery is fiddly or difficult (e.g. requiring a screwdriver). However, such constructions are less suitable for devices like wireless thermostats, where batteries need to be replaced more frequently.
Wireless devices also have the advantage of allowing installation in more convenient locations, where they are more accessible and hence typically also more visible. Users may therefore prefer to have devices whose appearance suits the environment in which they are installed. However, producing thermostats in a variety of designs to meet user needs significantly increases manufacturing costs.